This activity guides the analysis of a published scientific figure from a study that investigated how salt affects the electron transport chain.

High salt levels in soil and water, which can limit photosynthesis by plants and algae, is a growing concern for areas prone to drought and sea level rise. A key component of photosynthesis is the electron transport chain, which has two light-dependent parts: photosystem I and photosystem II. In this study, scientists measured how salt impacted the photosystems of a freshwater green algae species. The figure shows how different salt (NaCl) concentrations affect the ability of the photosystems, and the electron transport chain as a whole, to produce oxygen gas. The “Educator Materials” document includes a captioned figure, background information, graph interpretation, and discussion questions. The “Student Handout” includes a captioned figure and background information.